#include<iostream>
using namespace std;

int main(){
    int n,sum=0;
    double avg=0.0;
    cin>>n;
    for(int i=0;i<n;i++){
        int age;
        cin>>age;
        sum+=age;
    }
    
    avg=sum*1.0/n;
    printf("%.2lf",avg);
    return 0;
}
